Last updated on 6/5/2015 http://www.epa.gov/airquality/urbanair/



## Six Common Air Pollutants 

# What Are the Six Common Air Pollutants? The Clean Air Act requires EPA to set National Ambient Air Quality Standards for six comm on air pollutants. These commonly found air polluta nts (also known as "criteria pollutants") are found all over the United States. They are particle pollution (often referred to as p articulate matter), ground-level ozone, carbon mono xide, sulfur oxides, nitrogen oxides, and lead. These pollutants can har m your health and the environment, and cause property damage. Of the six pollutants, particle pollutio n and ground-level ozone are the most widespread health threats. EPA c alls these pollutants "criteria" air pollutants bec ause it regulates them by developing human health-b ased and/or environmentally-based criteria (science-based guide lines) for setting permissible levels. The set of l imits based on human health is called primary stand ards. Another set of limits intended to prevent environmental and property damage is called secondary standards. Click on one of the pollutants below for informatio n on sources of the pollutant, why the pollutant isof concern, health and environmental effects, effo rts underway to help reduce the pollutant, and other helpful resources. Ozone Particulate Matter Carbon Monoxide Nitrogen Oxides Sulfur Dioxide Lead Air Pollution Trends For each of these pollutants, EPA tracks two kinds of air pollution trends: air concentrations based o n actual measurements of pollutant concentrations i n the ambient (outside) air at selected monitoring sites throughout the cou ntry, and emissions based on engineering estimates of the total tons of pollutants released into the a ir each year. Despite the progress made in the last 30 years, millions of peo ple live in counties with monitor data showing unhe althy air for one or more of the six common air pol lutants. For EPA's most recent evaluation of air pollution trends for these six pollutants, click on the following: Latest Findings on National Air Quality: Status and Trends Health Effects Information Exposure to these pollutants is associated with num erous effects on human health, including increased respiratory symptoms, hospitalization for heart or lung diseases, and even premature death. Try these helpful resources: Air Quality Index (AQI) Ozone - Good Up High, Bad Nearby Ozone and Your Health Particle Pollution and Your Health Air Quality Guide for Ozone Air Quality Guide for Particle Pollution Smog - Who Does it Hurt? State Implementation Plan Status and Information EPA must designate areas as meeting (attainment) ornot meeting (nonattainment) the standard. The Clea n Air Act (CAA) requires states to develop a genera l plan to attain and maintain the NAAQS in all areas of the country and a specific plan to attain the standards for each ar ea designated nonattainment for a NAAQS. These plan s, known as State Implementation Plans or SIPs, are developed by stat e and local air quality management agencies and sub mitted to EPA for approval. Detailed information ab out state SIP elements and their status can be found on the State Implementation Plan Status and Information pa ge. 

# Six Common Air Pollutants | Air & Radiation | US EP A http://www.epa.gov/airquality/urbanair/

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